The cleverest San Andreas gets is surrounding a guy nicknamed "The Rock" with a heap of falling boulders.

Dwayne Johnson and his muscles come to the aid of Los Angeles and San Francisco when the two towns start to shake, rattle and roll, courtesy of humongous earthquakes erupting along the San Andreas Fault. But the cringeworthy dialogue and unmoving earnestness are the biggest disasters in this mostly forgettable action flick (* * out of four; rated PG-13; opens Friday nationwide).

Ray (Johnson) is an L.A. rescue helicopter pilot unafraid of jumping out midair to save damsels in distress, even when their car is hanging off a cliff. Things are arguably more hazardous on the homefront, where he has a rocky relationship with his soon-to-be ex-wife Emma (Carla Gugino); he worries about losing his daughter, Blake (Alexandra Daddario), to her mom's new rich boyfriend (Ioan Gruffudd at his smarmiest).

All that needs to be tabled when quakes annihilate the Hoover Dam and then move to California, where skyscrapers fall and bridges tumble dramatically. Blake gets lost in the streets of San Fran with a pair of English kids — one of whom (Hugo Johnstone-Burt) takes a shine to the girl, even with broken stone pillars screaming down upon them — and her parents reunite in order to bring her home safely. (It helps that Ray can drive pretty much anything with an engine.)

Paul Giamatti co-stars as Lawrence, a noted Cal Tech seismologist and the movie's resident science guy that no one listens to about the impending doom. While that subplot is largely inconsequential to the emotional core of the film, at least he's there for some of the scenes with true human peril.

Alexandra Daddario is trapped in a car and faces various other earthquake-induced dangers in 'San Andreas.'(Photo: Jasin Boland, Warner Bros.)

Director Brad Peyton (Journey 2: The Mysterious Island) spends much of San Andreas' running time on massive city destruction, but it's often a helicopter's eye view looking down, where humans are like ants simply falling to their fate. The most visceral scenes are when the camera is pointed up, with chunks of building tumbling or a huge boat coming over the crest of a tsunami, giving the audience a real sense of danger.

In a town that's short on macho action heroes these days, Johnson is probably the only man in Hollywood who looks like he could take on an earthquake and win. There are a few instances of the signature cinematic bravado he's shown in the Fast & Furious films and other projects — a cocked eyebrow here, a lighthearted one-liner there — but it's sorely lacking overall.

Johnson does what he can with the material, though no one is helped by Carlton Cuse's ham-fisted script. Many of the lines are met with a thud, and the worst of them induce groans and laughs: When Lawrence discusses history's biggest quakes in class, one student chirps, "Do you think something like that can happen here?"

Even for Rock fans and disaster-movie nerds, San Andreas is unlikely to move anyone in any real seismic way.